New television pictures from inside the crippled Three Mile Island (TMI) reactor--the first ever taken from the bottom of its reactor vessel--suggest that fuel did melt in a 1979 accident there. The pictures indicate that a 3-foot-deep deposit of debris has accumulated beneath the reactor core. In contrast to a statement issued after the preceding video survey in July 1982 (SN: 7/31/82, p. 68), GPU Nuclear Corp. now says, "Apparently, some of the debris was once molten." GPU Nuclear, which is directing the cleanup of the TMI unit-2 reactor damaged in the accident, is a subsidiary of the Parsippany, N.J.-based General Public Utilities, the plant's operator.

Unlike the first survey, made by inserting a camera 5 feet into the core area, the latest pictures were made possible by feeding the pencil-like 9-inch-long camera down the narrow passage between the side wall of the reactor vessel and the core's fuel assembly. What the fist-sized rocklike fragments (imaged in the center of photo) are made of is still unknown, according to Lisa Robinson, a GPU Nuclear spokesperson. However, she says, "Components that look like that don't exist in a normal reactor." Along with reactor-accident core-temperature estimates made by the Department of Energy last year during its examination of fragments of core rubble, Robinson says there is now evidence suggesting "that fuel melting did occur."

On the basis of this video survey, GPU nuclear now estimates that some 20 tons of debris litter the reactor vessel floor. As part of the cleanup effort, initial removal of fuel from the reactor is expected to begin sometime this summer.

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